1. Field of the Invention
This invention relates to a method of polishing a Cu film and to a method for manufacturing a semiconductor device.
2. Description of the Related Art
In the actual use of a Cu wiring, the polishing of the Cu film (a first metal polishing) is required to be performed in such a manner that the polishing rate of Cu film should be 1000 nm/min or more and that the polishing is stopped at a barrier metal with the dishing of Cu film being suppressed to 20 nm or less. Furthermore, the polishing of the barrier metal (a second metal polishing) to be performed subsequent to the first metal polishing is required to be performed in such a manner that the dishing of the Cu film, as well as the erosion of the insulating film should be suppressed to 20 nm or less in the step of exposing the surface of the insulating film.
In the case of a high-performance LSI of the next generation in particular, since a Low-k insulating film is employed in order to alleviate RC delay, it is required to take into account the peeling of the film or the fracture of the film itself. In view of these problems, it is required to perform the polishing at low friction and with high stability (preferably, without any substantial rise in temperature). However, it is difficult to realize such an ideal polishing using the conventional one-pack supply type slurry and the conventional apparatus.
With a view to prevent the stagnation of a polishing solution to be employed in the polishing and to prevent the flocculation or precipitation of abrasive grains, there has been proposed a two-pack supply type slurry. Further, with a view to prevent not only the enlargement of dishing but also the erosion of wirings, there has been proposed a two-pack supply type slurry which further comprises the supply of a surfactant.